Brake Booster Constantly Running (1 Viewer)

[svedank]

Howdy y'all. I'm a new fresh GX470 owner, bought a 2003 a couple weeks ago. There's a periodic chugging/cycling noise coming from the brake booster/accumulator/reservoir area that happens constantly when the ignition is turned to ON or the vehicle is running. Brakes work fine and there are no warning lights, but the vibration from the pump/motor can be felt through the pedal. I have a video of the noise but I'm still working on figuring out how to attach it here. I've posted this in the general section as I believe these types of assemblies are common across a lot of the Toyota trucks.

The PO says it's been there for the entire time he's owned the vehicle, about 8 years. I've flushed the very dark fluid that was in there but that has changed nothing. Could this have to do with a failed sensor or limit switch of some kind that's telling the motor to run every 5 seconds? Would like to avoid throwing parts at it up front if anyone has any ideas. Thanks!

 

[svedank]

Figured out the video... I think:

 

[rustybucket]

Never seen anything like it. Possibly there's a pump recharging the ABS accumulator? And it's got a leak so the pressure drops pressure sensor kicks on can pre charges the ABS accumulator again just a theory!

 

[svedank]

I think your theory makes sense. I've tried flushing and bleeding the fluid and rebuilding the master cylinder but I think I may have to try a new accumulator.

 

[crossmover]

I think your theory makes sense. I've tried flushing and bleeding the fluid and rebuilding the master cylinder but I think I may have to try a new accumulator.

Did a new accumulator fix it? My recently bought 2003 gx470 is doing the exact same thing and I’m wondering how to fix it without throwing tons of money at it.

 

[svedank]

I eventually fixed this issue by buying new OEM booster motor/pump/accumulator from Toyota ($815). I spent months troubleshooting and narrowed it down to both a worn out motor and accumulator that no longer held pressure. I had just acquired and planned to install a remanufactured motor (brushes, commutator, bearings, gasket) and new OEM accumulator with o-ring, spring, and pipe, however the old system failed about 700 miles from home before I got around to it, so I had to go to Plan B and buy new from the nearest dealer.

Are you interested in purchasing these parts I didn't install? It's the equivalent of P/N: 47070-30060. I can give you the details / photos / video of the motor running... would like to get $500 out of it.

 

[crossmover]

I eventually fixed this issue by buying new OEM booster motor/pump/accumulator from Toyota ($815). I spent months troubleshooting and narrowed it down to both a worn out motor and accumulator that no longer held pressure. I had just acquired and planned to install a remanufactured motor (brushes, commutator, bearings, gasket) and new OEM accumulator with o-ring, spring, and pipe, however the old system failed about 700 miles from home before I got around to it, so I had to go to Plan B and buy new from the nearest dealer.

Are you interested in purchasing these parts I didn't install? It's the equivalent of P/N: 47070-30060. I can give you the details / photos / video of the motor running... would like to get $500 out of it.

View attachment 2750894

View attachment 2750895

I eventually fixed this issue by buying new OEM booster motor/pump/accumulator from Toyota ($815). I spent months troubleshooting and narrowed it down to both a worn out motor and accumulator that no longer held pressure. I had just acquired and planned to install a remanufactured motor (brushes, commutator, bearings, gasket) and new OEM accumulator with o-ring, spring, and pipe, however the old system failed about 700 miles from home before I got around to it, so I had to go to Plan B and buy new from the nearest dealer.

Are you interested in purchasing these parts I didn't install? It's the equivalent of P/N: 47070-30060. I can give you the details / photos / video of the motor running... would like to get $500 out of it.

View attachment 2750894

View attachment 2750895

I installed a reman pump motor yesterday and the original problem still exists so I’m leaning on replacing the accumulator next. I did the replacement with MC on the vehicle and plan on doing the same with the accumulator. Would you sell just the accumulator and O ring? (Not sure if I need the spring and pipe).

 

[svedank]

Yeah I would sell you the accumulator separately. I think that was probably the bulk of my issue but the motor was just about toast as well. Shoot me a private message and we can work out the details. I'll probably just toss in the o-ring, spring, and pipe - they cost about $7 together.